Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Jul. 31, 2020
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	$ 52	$ 29
Effective tax rate	6.00%
Effective tax rate, excluding discrete tax benefits	2500.00%	24.00%
Federal statutory income tax rate	21.00%	21.00%
Income tax provision (benefit)	$ 12	$ (35)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	210	$ 22
Total amount of unrecognized tax benefits			$ 101
Unrecognized tax benefits, net of related deferred tax assets			61
Favorable net impact to income tax expense due to recognition of tax benefits			$ 61
Changes in unrecognized tax benefits	0
Noncurrent income taxes receivable	$ 61